MONTPELIER, Vt. (AP) _ Vermont on Wednesday became the first state to ban vehicles that use ozone- depleting chemicals in their air conditioning.

''Americans are ready to take tough actions to protect our fragile environment, even if it requires changing our own behavior or giving up certain luxuries,'' Gov. Madeleine Kunin said in signing the legislation into law.

''By enacting this important legislation, Vermonters are demonstrating that we are willing to act immediately to protect the stratospheric ozone layer,'' she said.

The ban covers the sale or registration of 1993 models that use chlorofluorocarbons, a class of chemical blamed for destroying the ozone layer that protects the Earth from the sun's harmful ultraviolet rays.

Car air conditioning systems are the single largest source of ozone depletion from the United States.

The legislation takes other, more immediate steps to reduce CFC emissions:

- Starting in 1991, equipment used to service air conditioners in vehicles must recycle the CFC coolant, rather than release it into the atmosphere.

- As of March 1, 1990, CFC recycling equipment must be used to service building air conditioners and large refrigeration units if such equipment is ''portable and suitable for those purposes.''

- The sale of CFC recharge kits will be prohibited so that consumers cannot circumvent the law's recycling requirements by servicing their own cars' air conditioning systems.

- The sale of CFC-based fire extinguishers, consumer cleaning sprays and CFC-propelled party streamers and horns is also prohibited.

Despite years of research into a replacement coolant, the nation's Big Three automakers have said they doubt they can meet the 1993 deadline.

''There is no way any manufacturer will be able to modify its entire car line for Vermont in essentially three years,'' Ford Motor Co. spokeswoman Beryl Goldsweig said earlier this month.